Improvement in saw-mills



o he regulated to suit the work.

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Letters Pate-nt No. 77,079, dated April 2 1, 1868..

IMPROVEMENT IN saw-MILLS.. o

TO ,ALL WHOM IT MAY CON CERN: l f Y Be it known that I, J. W.. MoYEIucfChei-ry Valley, in the'county of Otsego` and State of New York, have invented a new and improved Gig-Saw; and I do' ,hereby declare' the follow-ing to bea full, clear, and exact description of'the same, reference beinghad to the accompanying drawing, forming part of this specification, and which drawing represents a side' elevation o f my invention.

Myinvention consists in providing the saw-frame with two springs, one above and one below the saw, which operate togetherto give it thel necessary tension, vand which counteract each others eifect upon the motionof thesaw, renderingA its working even and uniform, and enabling it to be operated with any degree of speed.

In' the drawing, .A represents the ceiling, and B the floor of the room in which the saw S is operated, tire upper cud ofthe saw being hung'upon a lever or rocking-arm, C, supported by a frame, D, attached to the roofor ceiling oft-he room, and the lower end of vthe saw being hung upon'a similar lever, E, supported by a table, F, standing upon the floor. Y I l v lThe upperfand lower ends of .the saw run in guides g', to give it a perfectly even vertical motion. The saw is operated by a pitn'ran, G, worked by a shaft, I-I, to which power is applied ilu amyiconvenient manner. In the hanging and operating of the gig-saw, as so4 far described, there is nothing new except the use of .the levers or rocking-arms C E. 4

The essential feature of my invention consists in applying to the lower lever a spring, s, which forces it downward, and to the upper lever -a similar and equal spring, s, which forces it upward, so that the two springs assist each other to increasethc'tensionybut counteract each other in affecting the motion ofthe saw.

The springsvmay ,beof any convenient form, and may be as rigid and powerful as the size of thesaw and the nature ofthe work require. They may be attached to the levers themselves, operating directly upon them, as shown in the drawing, or they may be 'made vto operate upon the ends of the saw or. rods attached-to its ends, either in conjunction with the levers, or when the saw is not hung upon levers at all, but is held simply bythe guides y g', and worked directly by the pitman.

By the use oi the levers, as shown-in the drawing, the eifectof the springs upon the tension of the saw can be adjusted at pleasure, in a very convenient and simple manner. It is only necessary to provide a series, of notches, n n n n n n', along the side ofthe levernext to the spring, and a similar series` for the foot of the s rin to rest in, and shift the s rin from one notch to another of. thev series. It is evident at a lance that- P g P g g thc-nearer the spring approaches the saw, the more powerfully will it act upon its tension, so that the latter cany Machines have heretofore been constructed, and are irl/common use, in which one spring is employed, aet-4 ing above the saw to draw the latter up and give it tension. Such machines work very imperfectly, consuming -a .great deal of 'power to no purpose, and operating in ajerking, irregular mannerf; .for while theupperspring is acting alone, and the power applied at the working-shaft ishringing the saw down in its cutting-stroke, the

spring is all the while resisting the descent of the saw, and has to bc overcome by additional power applied to the shaft. At the instant, however, that the saw reaches the end of its descent, and beginsIto return, the spring' unites its force with that of the shaft, and the saw is thrown back with violence. Thus when erle spring is uscdalone, the power of the` shaft is interfered with and diminished on the descending cutting-stroke, where itis all needed, and on the return stroke, where little power is needed, the' spring unites its force with that ofthe shaft,-

and the two together drive the saw hack with great violence.I This can be easily demonstrated in my machine by removing the lower spring and workingwith the upper alone. But when both springs are used, the power that gives motion .to the saw is perfectly uniform, the shaft lexercises its full force onthe cutting-stroke, and no more than its own force on vthe return stroke, and the whole apparatus moves with silence and perfect regularity. While with one`spring the saw can'practically be driven, at the most, only three or four hundred strokes per minute, owingto the great irregnlaritypf its motion; with two it can he driven fifteen hundred, or faster, if desired, and yet silently and uniformly. This is of great practical utility, not only in saving time, but in the quality of the work, as the faster such a saw runs, the more even and smooth its work, and the lessvliahle it is to be crowded und warped or twisted by boing fed too fast. It will be quite impossible for the workman to feed my sow faster than it will out, and there will consequently be very little danger of its being warped or injured from any such cause. p

Having thus described my invention, what I claim as new, and desire 'to secure by Letters Potent, is

1. I claim the combination, with a/gig-saw, S, oftwo springsrs s', of equal power, the former at the upper end of the saw, and acting upwards upon it, and the latter at its lower end,'a.nd actingmdownwnrds upon it, all theI parts being constructed and combined, and operating together substantially in the manner and for tbe purposes set forth. y A

2. I claim the combination of the gig-saw S with the'notclled levers C E, andl equal springs s s', ull the parts being constructed and corbined substantially as :md for the purposes specified. Y

Y J.W. MOYER.

'Witnesses N. K. ELLswoRTu, J. W. MISTER. 

